Reduced Mechanical Wear: Factory-balanced design minimizes vibration

Dual-Speed Logic: Supports 2-speed motor operation for improved energy management and quieter cycling under partial loads

Common Questions What is the direct cross-reference for the 300051281

If you notice a "squealing" sound upon motor startup or a visible drop in 48-series rooftop unit airflow performance

Lochinvar & A.O. Smith 100112148 Switch 320788-704 Reduced Mechanical Wear: Factory-balanced designThe Lochinvar & A. O. Smith 100112148 Switch is a critical safety component designed for high efficiency water heaters and boilers. As a normally open pressure switch, it monitors negative air pressure created by the combustion air blower, ensuring the unit only proceeds to ignition once a proper draft is established. This genuine OEM replacement part is engineered to meet 2" WC specifications, providing the precision required to prevent hazardous gas